Table 3. Comparison of the different diagnostic criteria suggested for pyoderma gangrenosum ^{31, 34, 35}.

Proposed diagnostic criteria
Su et al. 34 criteria	The Delphi Consensus of International Experts	PARACELSUS score
Major criteria
Other ulcerating conditions excluded (that is, biopsy and other investigations)	Biopsy	Exclude other differential diagnoses
Typical clinical presentation of classic pyoderma gangrenosum a		Reddish-violaceous ulcer border
		Progressive ulceration (developed in <6 weeks)
Minor criteria b
Histopathology findings	Histopathology findings	Histopathology findings
Typical systemic diseases present	Typical systemic diseases present	Typical systemic diseases present inflammatory bowel disease, inflammatory arthritis
Treatment responsive to systemic steroids	Treatment responsive to immunosuppressants	Improvement in symptoms by immunosuppressants
History of pathergy and cribiform scarring	Pathergy	Pathergy
	Cribiform scarring
	Pain, undermined border, peripheral erythema	Undermined border
		Pain
	Papule, pustule, or vesicle that ulcerated	Irregular ulcer shape
	Multiple ulcerations (at least one on lower leg)

^aProgressive (1 to 2 cm/day or increase by 50% in 1 month), painful, irregular and undermined border, violaceous color, preceded by papule, pustule, or bulla.

^bFor the PARACELSUS score, minor criteria have a white background and additional criteria have a gray background.